Wednesday, January 30, 2008

A Pacemaker for Weight Loss?

It's always cool to hear about new ways pacemaker-like therapies can be used to improve patients' lives.

And now there might be some hope of using pacing therapy to help with weight loss by stimulating the vagus nerve. The company generating the most excitement right now is EnteroMedics. Using vagal nerve stimulation, they hope to decrease people's weight by 25%. Seems plausible, especially since stimulating the vagus nerve might cause early satiety. But the vagus nerve is also responsible for the SLUD syndrome: Salivation, Lacrimation, Urination and Defacation as well as heart rate slowing and the development of atrial fibrillation.

Unfortunately, the device still has to be surgically implanted - often under general anesthesia - and the risks of depressing respirations in morbidly obese individuals can be considerable. But, like bariatric surgery, if found to be effective and with few side effects, they might be on to something here.

I think anyone who is overweight might be a candidate for this device, irresective of the presence of atrial fibrillation or not, provided they're not a high surgical risk individual (companies want to have good outcomes during trials to improve their chances of FDA approval).

My point was that one well-established model for the development and maintenance of atrial fibrillation is vagal nerve stimulation. While vagal nerve stimulation can slow the overall heart rate by slowing the firing of the sinus node, it also shortens the refractory periods of atrial tissue and can facilitate the development and maintenance of atrial fibrillation.

I think the idea of these things is great, but I saw the results of some trials done by a similar device recently that revealed no significant change in EWL. They didn't meet their own definition of a successful endpoint (I believe 10% EWL is the standard.)

Wish I could remember the name of the physician so I could look up the trial and see if this new device is a new approach or a modification of the old.

If the anaesthesiologist is experienced in morbidly obese anaesthesia the chance of respiratory depression will be enormously low.

About Me

Westby G. Fisher, MD, FACC is a board certified internist, cardiologist, and cardiac electrophysiologist (doctor specializing in heart rhythm disorders) practicing at NorthShore University HealthSystem in Evanston, IL, USA and is a Clinical Associate Professor of Medicine at University of Chicago's Pritzker School of Medicine. He entered the blog-o-sphere in November, 2005.
DISCLAIMER: The opinions expressed in this blog are strictly the those of the author(s) and should not be construed as the opinion(s) or policy(ies) of NorthShore University HealthSystem, nor recommendations for your care or anyone else's. Please seek professional guidance instead.